Fabrication of Thin Palladium-Silver Alloy Film by Using Electroplating Technique

抄録

A thin Pd-Ag alloy film, which will be applied to fabricate membranes for hydrogen separation, was successfully deposited using an electroplating technique. The plating solution for the formation of a thin Ag-rich Ag-Pd film for electric contact consisted of PdCl₂, AgNO₃, HBr, and HNO₂. An improvement of the electrolytic bath was achieved by a pH control, which was kept constant at 6.6 and by the addition of H₃BO₃ and C₂H₅NO₂. When the concentration of PdCl₂ in the bath was increased to 4 times as high as that of the reported bath, the deposited film had the preferable composition of 72 mass% Pd and 28 mass% Ag. It was confirmed by SEM observations, and XRD, and EPMA analyses that the deposited film possessed a negligible amount of cracks and pinholes and was composed of Pd-Ag alloy without exhibiting any concentration gradient along the film thickness.